Ubiquinone (coenzyme Q) and the function of vitamin E

Effects of vitamin A and its analogs on nonenzymatic lipid peroxidation in rat brain mitochondria

Vitamin A (retinol) and some of its analogs exhibited varying degrees of inhibition on induced iron and ascorbic acid lipid peroxidation of rat brain mitochondria. Malonyldialdehyde production was used as an index of the extent of in vitro lipid peroxidation. The fat-soluble vitamins retinol, retinol acetate, retinoic acid, retinol palmitate, and retinal at concentrations between 0.1 and 10.0 mmol/L inhibited brain lipid peroxidation. Retinol and retinol acetate were the most effective inhibitors. It is concluded from this study that retinol and its analogs can be considered as potential antioxidant factors, more potent than some of the well-known antioxidants such as alpha-tocopherol and butylated hydroxytoluene.

The pathology of vitamin E deficiency in the chick

Syndromes of encephalomalacia, exudative diathesis and muscular dystrophy were produced in day-old chicks placed on a torula yeast base diet deficient in vitamin E. Changes in the percentage of dietary lipid were responsible for variation in the disease processes. Chicks receiving 3-9% lipid had vascular alterations which determined, in most cases, the severity of the resulting tissue changes. Encephalomalacia occurred only in chicks on 9% dietary lipid. Muscular lesions were seen in all chicks and were thought to be due to damage to the mitochondria. Acid phosphatase activity was not directly associated with degeneration of muscle.

The distribution and metabolism of alpha-tocopherol in the rat

1. A comparison of the distribution of radioactivity in rat tissue lipids after oral administra- tion of [5-Me-14C]-α-tocopherol showed that spleen and adrenal lipids have a relatively high uptake of radioactivity. 2. Absorbed α-tocopherol and its metabolites appeared not to re-enter the lumen of the gut in significant amount through the bile or by the secretion from the stomach mucosal cells within the 24 h experimental period. 3. After ingestion of [5-Me-14C]-α-tocopherol by rats, analyses of their liver and spleen lipids showed that most of the radioactivity in the lipids was due to the presence of unchanged α-tocopherol. Radioactive tocopherolquinone was found in both spleen and liver lipids; in the liver lipids there was some evidence that a second oxidation product of α-tocopherol, compound O, had been formed.

THE UBIQUINONE AND CRUDE STEROL CONTENT OF THE LIVER WITH VARIATIONS IN THE INTAKE OF TOCOPHEROL IN THE VITAMIN A DEFICIENT RAT

Some non-saponifiable constituents of rat liver have been studied in animals differing in their nutritional status in vitamin A and E. Liver levels of ubiquinone were negatively correlated with the vitamin A status of the animal but not with the vitamin E status. The crude sterol content of the liver was not affected by variations in the intake of either vitamin, except that there was a slight but significant increase when vitamin A deficiency was pronounced.

THE UBIQUINONE AND CRUDE STEROL CONTENT OF THE LIVER WITH VARIATIONS IN THE INTAKE OF TOCOPHEROL IN THE VITAMIN A DEFICIENT RAT

Some non-saponifiable constituents of rat liver have been studied in animals differing in their nutritional status in vitamin A and E. Liver levels of ubiquinone were negatively correlated with the vitamin A status of the animal but not with the vitamin E status. The crude sterol content of the liver was not affected by variations in the intake of either vitamin, except that there was a slight but significant increase when vitamin A deficiency was pronounced.